No, MAGI does not include the standard deduction. Your modified adjusted gross income is built from your adjusted gross income, and AGI is set before the standard deduction (or itemized deductions) is subtracted. Whether you take the standard deduction or itemize has no effect on your MAGI at all.
That answer matters because MAGI decides eligibility for Roth IRA contributions, Affordable Care Act premium tax credits, Medicare premium surcharges, the Net Investment Income Tax, and several other benefits. Assuming the standard deduction lowers the number the government looks at can lead to contributions you’re not allowed to make and credits you don’t actually qualify for.
Where AGI Ends and the Standard Deduction Begins
On Form 1040, adjusted gross income appears on line 11. It’s your total income minus a specific list of “above-the-line” deductions written into the tax code: educator expenses (up to $250), health savings account contributions, self-employment tax, and other items Congress has singled out.1Office of the Law Revision Counsel. 26 USC 62 – Adjusted Gross Income Defined
The standard deduction comes after that. The tax code defines taxable income as AGI minus either the standard deduction or itemized deductions, which makes those subtractions “below the line.”2Office of the Law Revision Counsel. 26 USC 63 – Taxable Income Defined They exist to shrink the number your tax is calculated on, not the number your eligibility is measured against. MAGI is built from the AGI line, so anything that happens below that line — the standard deduction included — never enters the calculation.
Why the Rule Is Written This Way
Programs tied to MAGI need a consistent measure of your resources across filers. The standard deduction is not the same for everyone: it’s larger for joint filers than for single filers, and larger still if you’re older or blind. If it fed into MAGI, a married couple and a single earner with identical income would look different to the ACA Marketplace, to Social Security, and to Medicare. Anchoring MAGI to AGI keeps the yardstick uniform regardless of filing status or whether you itemize.
What Actually Modifies AGI to Reach MAGI
Since the standard deduction is off the table, what does change your MAGI? Specific add-backs. You start with AGI and add certain items that the tax code excluded or deducted earlier. The list is short but it isn’t universal — the IRS uses different MAGI definitions for different tax benefits.3Internal Revenue Service. Modified Adjusted Gross Income
The foreign earned income exclusion and the foreign housing exclusion or deduction show up in nearly every version. Beyond that, the add-backs depend on which benefit you’re checking against. That’s why you may need to run the calculation more than once in the same year: your MAGI for a Roth IRA is not necessarily your MAGI for a premium tax credit or your MAGI for Medicare.
How MAGI Is Defined for the Main Programs
Roth IRA and Traditional IRA Deductions
For Roth IRA eligibility, MAGI is AGI plus the traditional IRA deduction, the student loan interest deduction, foreign earned income and housing exclusions, and certain adoption-related exclusions.4Office of the Law Revision Counsel. 26 USC 408A – Roth IRAs The same definition governs whether your traditional IRA contribution is deductible when you or your spouse is covered by a workplace retirement plan.
ACA Premium Tax Credit
For the Marketplace premium tax credit, MAGI is AGI plus three additions: foreign earned income excluded under Section 911, tax-exempt interest, and the nontaxable portion of your Social Security benefits.5Office of the Law Revision Counsel. 26 USC 36B – Refundable Credit for Coverage Under a Qualified Health Plan This version pulls in income streams that other MAGI definitions ignore.
Medicare Premium Surcharges (IRMAA)
Medicare uses your MAGI from two years earlier to decide whether you owe an Income-Related Monthly Adjustment Amount on Part B and Part D. For this program, MAGI is AGI plus tax-exempt bond interest.6Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles The formula is simple, but a one-time income event — selling a home, converting a traditional IRA to a Roth — can raise premiums two years later.
Education Benefits
For the student loan interest deduction, MAGI is AGI with the foreign earned income and housing exclusions added back, along with the exclusions available to residents of American Samoa and Puerto Rico.7Internal Revenue Service. Publication 970 (2025), Tax Benefits for Education – Section: Student Loan Interest Deduction The education savings bond program uses a similar approach, also adding back the savings bond interest exclusion and the student loan interest deduction.
Net Investment Income Tax
The 3.8% surtax on investment income applies when MAGI exceeds $200,000 (single), $250,000 (married filing jointly), or $125,000 (married filing separately). Those thresholds are fixed by statute and aren’t adjusted for inflation.8Office of the Law Revision Counsel. 26 USC 1411 – Imposition of Tax
In every one of these definitions, the starting point is AGI. The standard deduction is nowhere in the chain.
What a Wrong MAGI Number Can Cost You
Treating the standard deduction as if it reduced MAGI leads directly to two common errors.
The first is over-contributing to a Roth IRA. If your actual MAGI puts you past the phase-out limit and you contribute anyway, the IRS charges a 6% penalty on the excess for every year it stays in the account. You can avoid the penalty by withdrawing the excess contribution and any earnings on it before your tax filing deadline.9Internal Revenue Service. Retirement Topics – IRA Contribution Limits
The second is misstating income on a Marketplace application. Understating MAGI can produce premium tax credits larger than you qualify for, and you’ll owe the difference when you file. Overstating it can cost you credits you were entitled to claim.
The safest habit is to calculate MAGI separately for each benefit, following the instructions for that specific program. AGI is always the starting line. The standard deduction never is.